Pressure-control valve



sept. 11,- 1923.l

A. AMSLER PRESSUREv CONTROL VALVE l Filed March s1'. 1921 Smm Patented Sept. 1l, 1923.

UNITED STATES ALFRED AISLEB, 0F RHEINBUHL, SWITZERLAND.

PRESSURE-CONTROL VALVE.

Application led Hatch 31, 1921. Serial No. 457,480.

To all whomit may concern.'

Be it known that I, ALFRED AMsLnR, a citizen of the Republic of Switzerland, residing at Rheinbuhl, Schaifhausen, Switzerland, have invented certain new and useful Improvements in a Pressure-Control Valve; and I do hereby declare the following to be a clear, full, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being hadto the accompanying drawings, and 'to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to improvements in a device for automatically maintaining a constant pressure difference, i. e., a constant surplus pressure or over-pressure between two points of a pressure conduit.

A device of this type interposed for instance in the high pressure conduit leading to a hydraulic press serves to transmit liquid to said press at a uniform over pressure, which is regulatable at will within wide limits, whatever be the back pressure and the variations of back pressure in said press. In consequencelof the uniformity of this over-pressure, the piston of the press moves always at the same speed. Thereby it is assumed that the given liquid pressure is greater than that required in the press. In the device according to the inventionand inserted in the high pressure conduit leading to a press, the liquid under pressure is led into one of two intercommunicating chambers, an easily movable piston with a conical end being provided that automatically decreases the paage of the liquid to the press'cylinder sufficiently to maintain a constant difference 'between the incoming pressure and the back pressure when the pressure acting on the front end of said piston is greater than the back'pressure acting behind the piston, Said back pressure being equal to the pressure existing in the press cylinder plus a pressure exerted by aspring.

In a regularly acting pump there is always a certain quantity of liquid disposable per second, whose pressure depends on -Y the back pressure to overcome.

In a pressure accumulator the uantity of liquid disposable is so to say u imited,

whereas the pressure remains approximately constant.

For this reason the over-pressure regulator 1s executed in two forms which differ sllghtly from each other, one of these forms being intended for use with a hydraulic press receiving the liquid under pressure directly from a pump, and the other for use with a hydraulic press receiving the liquid from a pressure accumulator.

An adjustable valve is advantageously provided in the exit passage of the front chamber in order to allow of the speed of the liquid being regulated.

The accompanying drawing shows an example of each of the two above mentioned forms.

Fig. 1 is a longitudinal section of the first, and Fig. 2 a longitudinal section of the second form.

The over-pressure regulator illustrated in Fig. 1` is intended for use with a pump. The liquid under pressure passes from the pump, through conduit .4 into the front chamber 1 of cylinder 5. When the exit v passage of chamber' 1 is completely closed by means of point 7, the pressure rises therein and repels the piston 6 against the action of spring 8 until the liquid esca es into the ymiddle chamber2 and runs o As soon as the' outlet of chamber 1 is opened by screwing back point 7, the liquid contained in 'chamber 1 passes out into chamber 9 and from there through conduit 10 into the cylinder of the hydraulic press. Chamber 9V is connected to chamber 3 containing spring 8, by means of conduit 11,

the pressure'behind vthe piston in chamberA 3 is therefore the same as in chamber 9. The liquid pressure in chamber 3 to ether with the pressure exerted by the spring 8 tend to push the piston 6 forward and thus to prevent the liquid from runnin olf into the middle chamber 2. 0n the ront side of piston 6 there only acts the liquid pressure existing in chamber 1. l

When the piston 6 is equally balanced the pressures existing on either side thereof are 'equal to each other and to that of the pressure existingin chamber 3 plus that exerted by the spring, the pressure existing in chamber 9 being equal to that in chamber 3.

The difference between the pressures existing in chambers 1 and 9 is therefore constantly e ual to that exerted by spring 8.

When t e pressure in chamber lactmg on i the piston becomes slightly greater than the 'in chamber 9 and in the cylinder of the hydraulic press.

The quantity of liquid which passes through, depends on the size of the opening left free by the valve point 7 it increases thermore said valve point is screwed out, that is to say the larger the opening.

If durin a trial, the position of the valve point 7 is left unaltered, an equal quantity of liquid will alwayspass fromv chamber 1 to chamber 9.

The over pressure regulator shown in Fig. 2 is intended for use in connection witha pressure accumulator.

The liquid under pressure passes from the said accumulator through the conduit 4 into the middle chamber 2 of cylinder 5.

When the piston 6 is pushed forward, that is to say towards the chamber 1, the liquid is able to pass into the forward chamber 1 along the conical part 12 of piston 6.

This second form is otherwise similar in construction to that shown in Fig. 1.

When the valve point 7 shuts off the chamber 1, as shown in the drawing, the liquid comingv from the lchamber 1 cannot pass, the pressurel is therefore equal to that existing in chamber 2.

Piston 6 is pressed backwards against the action of spring 8, the cone 12 thereupon shutting off the communication between chambers 1 and 2.

Should the outlet of chamber 1 be slightly opened by unscrewing point 7, the liquid may pass from 1 into chamber 9 and from here through conduit 10 into the cylinder of the hydraulic press.

When the valve is open and balanced the difference of pressure between chambers 1 and 9 is equal to the pressure exerted by spring 8.

If the pressure exerted on the piston in chamber 1 becomes greater than the back pressure behind the piston 6, the latter Ifeturns and closes the passage between 2 and 1 sufficiently so that only the amount of liquid is allowed to pass which is required to reestablish the equilibrium of the piston. The liquid flows from 1 to 10 under constant pressure, whatever be the back pressure existing in chamber 9 and in the cylinder of the press. Y

The over pressure regulator according to the present invention is advantageously used in connection with all presses worked by the pressure of liquids where it is important that the piston rises at a constant speed what- The ever be the resistance to overcome said speed being adjustable at will during the operation cf the press. Machines of this kind are utilised to operate testing .machinery or to press dough-like substance into bands, strings or tubes, for instance gunpowder presses, pencil presses, lead wire or tube presses, macaroni presses and the like.

It is only necessary, in order to be able to mount the over pressure regulator in the high pressure conduit leading to the press that the available pressure be greater than that required in the press or to surmount the pressure exerted by the sprinfr inthe regulators, it is not necessary that t e pump work regularly or levenly or that the pressure in the accumulator be constant. The fact that the piston establishes the connection between chambers l and 2 in such a manner that the liquid passes at constant pressure from 1 to2 prevents a shock in the conduit 4 from producing a shock in the conduit 10. f-

A hydraulic press fitted with an over pressure regulator willv thereforeact as re-.

gards uniformity of working in the same manner as a mechanically operated screw press working at a uniform speed, the advantage being that the former is rapidly adjustable during operation, easily develops great power, works fast with but a small consumption and has a high ,efliciency I claim:

l. In a device for automatically maintaining a constant pressure difference between two points of a pressure fluid conduit, in combination, two chambers, one of which is connected to the incoming pressure conduit, a connection between the two chambers and a connection between one of said lou chambers and the outgoing conduit, a fioating piston having equal effective areas at .both ends when fluid is passing through said device and adapted to automatically control said connection between said two chambers, the incoming fluid pressure tending to move said piston in onedirection and the back pressure existing in the outgoing conduit increased by an additional pressure tending to move said piston in the other direction, the control being so effected that the pressureexisting in the chamber connected to the outgoing pressure conduit is always higher than the back pressure in the outgoing conduit by the amount of said additional pressure applied to the controlling piston, whatever be the absolute pressures and the variation thereof.

2. In a device for automatically maintaining a constant pressure difference between two points of a pressure fluid conduit, in combination, two chambers, one of which is connected to the incoming pressure conduit, a cylindrical bore connecting said two chambers and a connection between one of the chambers and the outgoing conduit, a floating pisto-n having, when fluid is passing through said device, equal effective working sections at both ends corresponding to said cylinder bore and provided with a tapering portion adapted lto move in said bore, the incoming pressure tending t0 move said piston in one direction and the back pressure existing in the outgoing conduit increased by a spring pressure tending to move said piston in the other direction, the cont-rol being so effected that the pressure existing in the chamber connected to the outgoing pressure conduit is always higher than the back pressure in the outgoing conduit by the amount of said spring pressure applied to the controlling piston whatever be the back pressure and the VariatiOnsthereO.

3. In a device for automatically maintaining a constant pressure difference between two points of a piessure fluid conduit, in combination, a chamber connected to the incoming pressure conduit and to the outgoing conduit, a second chamber provided with a free discharge opening, a cylindrical bore connecting said two chambers, a floating piston provided with a tapering end adapted to control the flow through said bore and ending within the first mentioned chamber so that the pressure of the incoming conduit acts on this end of said piston, a connection from the outgoing conduit to the other end of said piston so that the back pressure acts on the other end of the piston, a compression spring adapted tov act on the other end of said piston so that the conical end of said piston adjusts itself automatically in such a position within said bore that the pressure inside the first mentioned chamber connected to the outgoing conduit corresponds always to the back pressure increased by said spring pressure and a constant pressure difference equal t0 said pressure of the spring is maintained between said first mentioned chamber and the outgoing conduit, whatever be the back pressure and the alterations thereof.

4. In a device for automatically maintaining a constant pressure difference between two points ot a pressure fluid conduit, in combination, two chambers one of which is connected to the incoming pressure conduit,

a cylindrical bore connecting said two chambers and a connection between one of said chambers and the outgoing conduit, a floating piston provided with a tapering portion adapted to move in said bore and arranged'so that the incoming fluid pressure tends to move said piston in one direction and the back pressure existing in the outgoing conduit increased by a spring pressure tends to move said piston in the other direction, the controlling being thus so effect-ed that the pressure existing in the chamber connected to the outgoing pressure conduit is always higher than the .back pressure in the`outgoing conduit by the amount of said spring pressure applied to the controlling piston whatever be the back pressure and the variations thereof, and means for regulating at any instant the quantity of fiuid passing through the said connection between one of the cham- 4bers and the outgoing conduit.

5. In a device for automatically maintaining a constant pressure difference between two points of a pressure fluid conduit, in combination, two chambers, one of which is Y connected to the incoming pressure conduit,

a cylindrical bore connecting said two chambers and a connection between one of said chambers and the outgoing conduit, a floating piston provided with a tapering portion adapted to move in said bore and arranged so that the incoming fluid pressure tends to move saidpiston in one direction and the back pressure existing in the outgoing conduit increased by a spring pressure tends to move said piston in the other direction, the controlling being thus so effected that the pressure existing in the chamber connected to the outgoing pressure conduit is always higher than the back pressure in the outgoing conduit by the amount of said spring pressure applied to the controlling piston whatever be the back pressure and the variations thereot, and an adjustable valve for vregulating at any instant the quantity of fluid passing through the said connection between one of the chambers and the outgoing conduit.

In testimony that I claim the foregoing as my invention, I have signed my name. 

